For composting to be most effective you need to start with a large mass of organic material. The larger the mass, the more effective the composting. Typically, this mass is called a compost pile. A minimum pile size of three feet by three feet by three feet is recommended, though I suggest a pile with dimensions of four feet by four feet by four feet. When the microorganisms begin decomposing organic matter they generate heat and that heat helps the organisms to multiply and accelerate the decomposition. The bigger the pile, the faster it turns into compost.
The compost pile can be literally a pile that you place in a corner of your yard or garden. It can also be contained in a structure of wood or plastic. There are many products on the market for holding the organic material while it turns into compost. They fall into two basic categories: those that are open and those that are closed. The container or structure isn't nearly as important as the material and the size of the mass.
The only other things they need are water and air. Food, water, and oxygen are the basics of life. The organic material is the food, rain and water from your hose supplies the second component, and the air all around us provides oxygen. You don't need to buy anything to make a compost pile and start the little buggers working; everything needed is already prevalent in nature.
Be aware of the concept of greens and browns and always try to have more browns than greens, but there should always be a blend. If your pile seems to have a lot of greens, add some brown; if it has a lot of browns, add a little green. What does this really mean?
Greens that you would compost are fresh-cut grass, weeds that you just pulled, banana peels and vegetable scraps from your kitchen, and any other plant material that is fresh. Browns that you would compost are dried leaves, straw, shredded newspaper, pruned branches, and any other plant-based material that is old and dried out. On the surface, if the material is green, orange, yellow, or red, it should probably be considered a green/nitrogen component. If it is brown, black, or tan, it should be considered a brown/carbon component.
As you create your compost pile the ratio of greens to browns is important, but you'll see many different recommendations for what is best. Colorado State University suggests starting a compost pile with alternating six to eight-inch layers of green and brown, a 1:1 mix. I've seen one reputable source that suggests 30 parts carbon to one part nitrogen, a 30:1 mix. Another recommends four parts brown to one part green, a 4:1 mix. If it seems confusing it is, because everyone seems to have a different formula. What is consistent in all recommendations is that nitrogen, the green, should not be the dominant material; too much green material can become smelly and not decompose well. Conversely, too much brown material will take a very long time to break down.
Unless you've planned well in advance, you won't have enough material to create a pile that starts out with the four-feet dimensions I recommend. So start with what you have. Throw your yard and kitchen waste on the pile. As you build it be aware of the green-brown mix and modify your additions appropriately. When I mow my lawn I use a mulching mower and leave the clippings on the grass; it's good for your lawn to do that. If I find that most of what I have in my pile is brown material, I'll put the bag on the mower to catch some of the clippings and add them to the pile. If I find that I've added a lot of green material recently, I'll make a point to throw in some straw or dried leaves that I saved from fall clean up.
Keep adding to the pile and it will eventually reach suitable mass. As it grows it will begin decomposing, but it really starts to cook when it reaches about three feet in size. And cook is a literal term. The temperature in a compost pile can easily reach 120F to 150F degrees. The bigger the pile and the better the blend of green and brown, the hotter it gets. At those temperatures the microorganisms are incredibly efficient. They're like college students on spring break in Mexico; they can't stop eating and multiplying in the heat. By the time your pile reaches four-feet in size, everything is in place for the creation of rich, black compost.
It's at that point that I stop adding to the pile. The whole point of the pile is to create compost and if you're always adding to it it is never fully decomposed. When it reaches optimum mass, let the organisms do what they do best, eat. The pile will decrease in size; the volume of the material is reduced by 50 to 75 percent. What used to be grass, and leaves, and vegetable peels will no longer be identifiable as it all begins to look dark brown and crumbly.
Because you've added material to the pile over time, some of it will be more decomposed than the rest. You'll have a mix of small, fully decomposed pieces along with partially decomposed, bigger pieces. Eventually all of the material will decompose into small particles that resemble a fluffy soil.
When it has decomposed to a point that you're ready to use it, use it. I will take some of the partially decomposed compost, when the pieces are still chunky and big, and use it as mulch in my vegetable garden. It does all of the good things that mulch does and when I turn over the soil in fall or early spring it becomes a soil amendment. I'll use fully decomposed compost to amend the soil at planting time.
Of course, I have more than one compost pile. When I stop adding to one because it reaches appropriate size, I begin a new pile. Just about the time the second pile is full, the first pile is fully decomposed and ready to use. I use this two-pile system to deal with the amount of organic waste my household and garden produces. More waste can support more and bigger piles.